Electric-motor controlling device



(o Model.) 2 Sheets-Sheet I. J. E. STANTON.

ELECTRIC MOTOR CCNTECLLINC DEVICE. No. 513,213. Patented Jan. 23, 1894.

Wl'rNEssEs Fig.; INJENTDR iNo Model.

2 Sheets-Sheet 2. J. E. STANTON. ELECTRIC MOTOR GONTROLLING DEVICE. No.513,213. Patented Jan. 23, 1894.

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rigf. WITEESES IM/ENTI: aka/@ @WM UNITED STATES PATENT OFFICE.

.TERE E. STANTON, OF BOSTON, MASSACHUSETTS.

ELECTRIC-MOTOR CONTROLLING DEVICE.

Application filed J une 19, 1893.

To all whom, t may concern:

Be it known that I, .TERE E. STANTON, of Boston, in the county ofSuffolk and State of Massachusetts, have invented new and usefulImprovements in Electric-Motor Controlling Devices, of which thefollowing, taken in connection with the accompanying drawings, is aspecification.

My invention consists of an improved controlling device for electricmotors whereby the motor may be instantly started, stopped reversed orvaried in speed in either direction by the foot of the operator.

There are various machines to which electric motors are applicable forfurnishing the motive power in which it is desirable to have the speedeither direct or reverse not only under immediate control, but capableof being controlled in such a manner that the operator has both handsfree at all times for the particular manipulation of the machine; suchfor instance is a dental engine which it is often desirable to varygreatly in speed and sometimes to quickly reverse without using eitherhand for the purpose.

It is with special reference to dental and surgical engines that myimproved motor controlling device has been contrived, though it isequally applicable to a great variety of uses wherein the electric motorsupplies the power.

The device consists of a pivoted pedal capable of being moved to theright or left by a turn of the foot. Connected with the pedal andmovable therewith is an arm which is adapted to traverse a series ofcontact posts, throwing into circuit varying sections of resistancecoil, on either side of the central or neutral point of the arm. Thisarm also operates a peculiarly contrived switch, the construction beingsuch that when the pedal is in its central position the circuit is open;and when moved to one side, the arm, working in connection with theswitch, brings into circuit through the motor, coils of varyingresistance, thereby varying the speed at will'.

Referring to the accompanying drawings Figure 1 is a top plan view of acontrolling device embodying my invention. Fig. 2. is a plan view of theinterior mechanism, the top Serial No. 478,063. (No model.)

of the inclosing case being removed. Fig. 3. is a transverse sectionalview through the center of the apparatus and Fig. 4. is a plan view inthe nature of a diagram showing the method of connection between thebattery, the motor and the various working parts of the controller.

A is the base board of the controller case and A is the top which isadapted to be screwed or otherwise attached to the sides of the case.

B is the operating pedal secured to the pivotal arbor b3 which turnseasily within the top A.

C is an arm within the case connected with the pedal in such a manner asto be movable conjointly therewith. As herein shown the inner end c ofthe arm C has bearings between the bracket H and the plate H secured tothe bottom of the case, and the downwardly project-ing arbor b3interlocks with the part c in such a manner that both the pedal and thearm are movable together about the same axis which is preferably in thecenter of the heel of the operators foot as it rests upon the pedal. Thepedal B at a point beneath the ball of the foot preferably has a bearingupon the arc shaped piece B2 as the pedal is moved to the right or leftabout its axis by a turn of the foot.

The arm C is virtually a bell crank lever the shorter arm C2 beingpivotally connected through the link L with the sliding switchconsisting of the slotted piece L of non-conducting material (guided tomove back and forth over screws set in the base) and of the springcontact pieces L2 L3 Secured to the sides of the movable non-conductingpiece L.

F F F4 are plates along which the contact piece L2 is adapted to slideas the switch moves, while F2 F3 and F5 are corresponding plates for thecontact piece L2, the parts be ing so arranged that the spring pieces L2and L3 are always in contact with the plates F4 and F5 respectivelywhatever the position of` the arm C; if the arm C is moved to the rightsaid plates FAl and F5 are connected through the contact pieces with theplates F and F3 respectively. If the arm C is moved to the right.

the left, the plates F4 and F-5 are connected through the 'contactpieces with the plates F and F2 respectively. The insulation f separatesthe plates F and F' while the insulation f' separates the plates F2 andF2.

Conducting cross strips G and G serve to connect in pairs the plates FF2 and F F2, said conducting strips being carefully insulated from eachother.

When the arm C is in its central position the forward end C' thereofrests upon the neutral plate d. When moved to the right the part C' ofthe arm traverses a series of contact posts cl' cl2-d' at various stagesalong a resistance coil D. de ri-d are corresponding series of contactpieces to the left of the central or neutral point d, connected atvarious points with the resistance coil D'.

The coils D D' are preferably arranged on the under side of thenon-conducting plate E between it and the bottom Aof theinclosing case.

B' is an index on the front of the pedal B, whichin connection with theplates b b' and b2 indicateto the operator when the armO 1s on theneutral point d or in the contact posts da or d'.

The generator or source of electrical supply is in the present case astorage battery, represented by Rin the diagram in Fig. 4, while M isthetield and N the brushes of the motor to be controlled.

The wires o oo11 connect the various parts of themechanism ot' thecontroller with themotor and' battery through the binding posts alongthe s i'de of the case, the particular arrangement of the connectingwires being obvious from the operation of the mechanism which will nowbe described. v Suppose the motor to be driven with a direct or righthanded motion by turning the pedal to When the pedal is on the centralor neutral 'point the motor is stopped since in that position thecircuit is broken. By turn-v ing the pedal to the left the currentisturned in the opposite direction through the motor which is thusreversed. The speed either director reverse is vat its minimum when thepartC' of the arm C is on the posts d' or d8 and its maximum when thepart C' is on the posts d7 or di".

Suppose the pedal to be moved tothe right with the part C on the contactpost d'. In this position the sliding switch by means of the springcontacts L2 L3 connect the plates F' and F 4 on one side and the platesF3 and F5 on the other. The track of the current from the storagebattery is then traced as follows:from the battery along wire o,`through binding post R' to bracket H,.arm C C' to'contact post d'through coil D to d7, through wires o2 and oB to plate F4, thencethrough contact spring L2 to plate F', and from there through strip G toplate F2, then through wire o4 to binding post N', to wire o5,

to brushes N on the motor, to wire o6, binding post N2, wire o2 to plateF, through strip G' to plate F2, through contact piece L3 to plate F5,through wire os to binding post M', wire 09 through eld M of motor, wire010 binding post M2 and wire 011 back to battery.

If the pedal be turned to the extreme right with the parat C' on thecontact post (i7 the resistance coil D will be cut out of the abovecircuit and the speed will of course be greatest, the speed beingproportional to the amount of the resistance coil put in circuit,

`or, in other Words, with the angular position of the pedal.

with the pedal B to the left of the neutral' point, say with the part C'of the arm C on the contact post d2,t he switch L is moved forward andthe track of the current is thus tracedz--from-battery R along wire o tobinding post R', wire Q ',bracket H, arm C C', contactpost d2, coil'D',wire o2, plate-F4, contactA pieceL2, plate F, wire o2, binding-post N2,

wire o, motor-brushes N, wire 0,"bindingpost N', wire o4, plate F2contact piece L2, plate F5, wire o8, binding postV M', wire 09,-' motorfield M, wire 010, bindingjpost M2, Wirefou'back to battery. u

P. representsthe pulley of the motor from which through the beltsP'power is transmitted to the dental engine or other machine to be driven.V

The inclosing case withthe controller therein rests preferably upon theiioorv near-the machine to be operated, in such a; position that theoperator by a very slight movement of the foot upon the pedal may atwill instantly vary the speed and directionof movement in accordancewith the particular work to be done and in avery simple manner, havingboth hands free for the manipulation of the machine. c

I claim-a 1. In combination, au electric circuitthrough a motor andgenerator, a pedal operatedpivoted arm forming a terminal of thecircuit, a resistance coil on each side of the arm, each coil beingprovided with contact postsat various stages ot' said coil adapted to betraversed by said arm, a sliding switch oper'- ated by said arm, andsuitable contacts for said switch whereby a greater or less portionl ofeither coil may be t-hrownintocircuit and the current sent through themotor in one direction or the other and in varying intensity accordingto the positions'of the armV and switch substantially as described.

2. In combination, an electric circuit'through a motor and generator,the` laterally movable pivoted pedal B, the bell crank lever C C2movable with, and about the same axis as the vpe`dal,resistance coils DD' having contact posts adapted to be traversed by the long arm of saidlever, the sliding switch L L2Ls movable bysaid lever, contact plates F,F',

F2 F3, F4 F5, and suitably arranged conduc- IOO part of a circuitthrough a motor and generator substantially as described.

In testimony whereof I have signed my name to this specification, in thepresence of 15 two subscribingr witnesses, on this 10th day of February,A. D. 1893.

J ERE E. STANTON.

Witnesses:

ALBERT E. LEAOH, M. T. LEAOH.

